The issue is it would actually have to be implemented at the access point (to assume both connections are one pipe rather than just giving your computer two different IP addresses). You'd have to hack your router first to allow such a thing.

I did try out connecting at 2 frequencies (dual band router and 5.6GHz connection + 2.4 GHz connection) - it just gave the PC two IP addresses and Windows would choose one of the two connections via a fixed priority.

__________________"The computer programmer says they should drive the car around the block and see if the tire fixes itself." [src]

802.11n already uses MIMO and channel bonding to achieve it's 150-450Mbps as part of the protocol/standard which is kind of what LACP (802.3ad) for Ethernet does to combine interfaces to get additional speed.

There's nothing you can do to make it any better, other than finding channels with minimal interference which is increasingly difficult these days since everyone has WiFi and cordless phones.